Ground fault circuit interrupting (GFCI) devices have gained wide usage as a safety measure to prevent injurious electrical shock occasioned by ground faults. Electrical equipment manufacturers have found it possible to combine the ground fault interrupting capability with the overload and short circuit interrupting capability of conventional automatic electric circuit breakers in a molded case compatible in size with conventional circuit breakers so as to be acceptable in existing electrical service entry equipment. Consequently, GFCI circuit breakers can be conveniently installed in place of conventional circuit breakers to gain ground fault shock prevention without sacrificing the requisite elements of circuit protection.
A significant drawback engendered by combining the shock protective and circuit protective functions with a single circuit breaking mechanism is the inability to distinguish between which of the functions triggered the circuit breaking mechanism to interrupt the circuit. If, upon contact with an appliance, one experiences a momentary electrical shock as the GFCI circuit breaker trips, it is manifest that the shock perfective function was responsible for the circuit interruption. However, occasionally one will discover a dead circuit and find that the GFCI circuit breaker has tripped for no apparent reason. From a trouble-shooting standpoint, it would be most helpful to know whether the GFCI circuit breaker tripped because of an overcurrent condition or because of spurious ground leakage current caused, for example, by a breakdown of the electrical insulation of the wiring or the appliance connected thereto.
It is accordingly an object of the present invention to provide a circuit breaker having overcurrent and ground fault protective capabilities which includes means for indicating which of the protective capabilities was operative to initiate a trip function.
A further object of the present invention is to provide a GFCI circuit breaker of the above character, wherein the indicating means is selectively conditioned automatically incident to tripping of the circuit breaker.
Yet another object of the present invention is to provide a GFCI circuit breaker of the above character, wherein the indication manifested by the indicating means is sustained until the circuit breaker is manually reset.
A further object of the present invention is to provide a GFCI circuit breaker of the above character which is economical and compact in design and reliable in operation.
Other objects of the invention will in part be obvious and in part appear here and after.